Search results for "Age structure"
showing 10 items of 17 documents
Lack of specialist nidicoles as a characteristic of mite assemblages inhabiting nests of the ground-nesting wood warbler, Phylloscopus sibilatrix (Av…
2021
AbstractBird and mammal nests provide microhabitats that support a range of other species, including invertebrates. However, the variation between communities of nest-dwelling invertebrates in different nests is poorly understood. The major aim of this study was to analyze the assemblage structure of mites from the suborder Uropodina (Acari: Mesostigmata) and from superfamily Crotonioidea (Acari: Oribatida) inhabiting nests of the wood warbler, Phylloscopus sibilatrix (Aves: Passeriformes), located on a forest floor in Białowieża Forest, in eastern Poland. We also assessed the correlation between the nest material used by the birds with the assemblage structure of Uropodina mites, and compa…
Age structure in a newly established and increasing population: initially high proportion of young birds among nesting Great Grey Owls
2020
AbstractThe mechanisms behind expansions of the distribution of a bird species and the ensuing establishment of new populations are poorly known. The distribution of Great Grey Owl (Strix nebulosa) in the western Palearctic has generally expanded towards southwest during the past fifty years, and particularly so in Fennoscandia. In the past decade, the recorded breeding population in Norway, confined to Hedmark county bordering Sweden, increased from 1 pair in 2009 to > 100 pairs in 2017–2018, extending the southwestern border of the distribution > 100 km. We studied the age structure of this expanding population based on the molting pattern of the wing feathers of birds captured at t…
Death certificate only proportions should be age adjusted in studies comparing cancer survival across populations and over time
2015
Abstract Background The proportion of cases notified by death certificate only (DCO) is a commonly used data quality indicator in studies comparing cancer survival across regions and over time. We aimed to assess dependence of DCO proportions on the age structure of cancer patients. Methods Using data from a national cancer survival study in Germany, we determined age specific and overall (crude) DCO proportions for 24 common forms of cancer. We then derived overall (crude) DCO proportions expected in case of shifts of the age distribution of the cancer populations by 5 and 10 years, respectively, assuming age specific DCO proportions to remain constant. Results Median DCO proportions acros…
Technological change and wage premiums: historical evidence from linked employer-employee data
2013
This study analyses the impacts of a technological change (the steam engine) on wage premiums. Using historical employer–employee panel data, we found that steam technology had both new skill-demanding and skill-replacing aspects. The former manifested itself as an increase in the demand for high-skilled engineers, the latter in a decline in the demand for intermediate-skilled, able-bodied seamen and an increase in the demand for unskilled engine room operators. Our panel data analysis, which controls for unobserved heterogeneity, implies that high-skilled labourers in abstract tasks and unskilled labourers in manual tasks improved their wage positions relative to intermediate-skilled labou…
Seismic Performance of Earthquake-Resilient RC Frames Made with HSTC Beams and Friction Damper Devices
2021
Seismic behavior of RC frames with hybrid steel-trussed concrete beams is affected by panel zone damage due to a large amount of longitudinal reinforcement. Here the seismic efficiency of innovative frames characterized by friction damper devices (FDDs) at beam-to-column connections is compared against traditional frame. Three configurations are investigated: FDDs alone; FDDs with column-to-foundation connections having preloaded threaded bars and disk springs; FDDs with self-centering friction devices. Non-linear analyses show that FDDs alone prevent plastic hinge formation at beam ends and beam–column joint damage. FDDs with self-centering friction devices effectively limit both peak and …
From pragmatics to semantics:Esto esin formulaic expressions
2006
Abstract This paper explores the transition of the Spanish marker esto es (English that is) from a free construction into a reformulative marker, as well as the pragmatic variables involved in this shift. Based on the occurrences of esto es between the 13th and the 15th centuries in the CORDE corpus, the study shows that, in order to account for this change, external factors have to be considered, especially the discourse traditions associated with the texts in which this marker appears. If this hypothesis is correct, then the problem of the pragmatics-semantics interface will have to include a new front, where non-linguistic factors trigger changes in language structure.
Dinosaurian survivorship schedules revisited: new insights from an age‐structured population model
2021
Little is known of dinosaur population biology due to insufficient information on age‐dependent fecundities and mortalities. So far, survivorship curves (SC) of only six dinosaurs (four tyrannosaurs, one ceratopsian, one hadrosaur) have been erected from bone assemblages of aged specimens. They indicate high survival throughout most of their life with presumably higher mortalities after hatching and increasing mortalities towards its end. However, none of these studies recognized that to infer a reliable SC for a taxon, the assemblage must preserve a stationary age distribution (i.e. one which is stable, with constant population size over time as overall fecundities match mortalities, herea…
Looking for the Easy Way Out : Demographic Panic and the Twists and Turns of Long-Term Care Policy in Finland
2019
This chapter aims to map the twists and turns in the development of long-term care policy in Finland since the start of the 1990s. The main argument of the chapter is that these changes have to a large part been motivated by what is called here ‘demographic panic’, that is, fear of consequences of population ageing to the public purse. Various policy changes have taken place during the last three decades. Since the late 1980s, Finnish long-term care policies have been made under the shadow of the ‘demographic time bomb’ discourse that argues that care expenditures are to rise exponentially if determined action is not taken to curb the expenditures. As a result, the focus of policy has been …
Contrasting age-specific recruitment and survival at different spatial scales: A case study with the European storm petrel
2009
Evolutionary studies on optimal decisions or conservation guidelines are often derived by generalising patterns from a single population, while inter-population variability in life-history traits is seldom considered. We investigated here how survival and recruitment probabilities changed with age at different geographical scales using the encounter histories of 5523 European storm petrels from three Mediterranean colonies, and also how our estimates of these parameters might be expected to affect population growth rates using population matrix models. We recorded similar patterns among colonies, but also important biological differences. Local survival, recruitment and breeding success inc…
The Age Structure of Human Capital and Economic Growth
2018
This paper shows that the age structure of human capital is a relevant characteristic to take into account when analysing the role of human capital in economic growth. The effect of an increase in the education of the population aged 40–49 years is found to be an order of magnitude larger than an increase in the education attained by any other age cohort. The results are unlikely to be driven by the age structure of the population, as we find that the effects on growth of the age structure of education and the age structure of population are distinct. The findings are robust across specifications and remain unchanged when we control for long‐delayed effects in human capital or for the exper…